ST. PETERSBURG, Fla.  The Padres made several lineup adjustments Saturday afternoon to pave the way for the major league debut of 23-year-old Burch Smith.

Right-handed reliever Brad Boxberger was optioned back to Triple-A Tucson to create a spot on the 25-man roster. And right-handed reliever Fautino De Los Santos, who was a waiver claim by the Padres in February, was designated for assignment to clear a spot on the 40-man roster.

Smith has been promoted from Double-A San Antonio to take Clayton Richard’s spot in the rotation.

Richard, who went on the disabled list last Sunday with an intestinal disorder, pitched a three-inning simulated game at Tropicana Field Saturday and will make a Triple-A rehab start for Tucson at Iowa City next Thursday.

Smith is the third Padres starting pitcher to make his major league debut – and the first since 2002 when both Oliver Perez then Jake Peavy made their debuts against American League teams.

The 6-foot-4, 195-pound Smith will probably be limited to around 90 pitches Saturday (3:10 p.m.) as the Padres try to even their three-game series at Tampa Bay after the Rays won Friday night’s opener 6-3.

The right-handed Smith has a fastball that reaches 98 mph.

The Padres have loaded their lineup with left-handed bats against Rays starter Jeremy Hellickson.

Mark Kotsay, who hasn’t played since April 30 in Chicago due to a sore back, will be the Padres designated hitter. Alexi Amarista will be in center fielder and Will Venable in right. Carlos Quentin, who was the designated hitter Friday night, will be in left.

John Baker will catch Smith’s major league debut.

Including switch-hitters Everth Cabrera and Chase Headley, the Padres will employ seven left-handed bats Saturday with the only right-handed-hitting starters being Quentin and rookie second baseman Jedd Gyorko.

PADRES (16-19) at RAYS (17-18)

Time: 3:10 p.m. Game: 2 of 3

TV: Fox Sports San Diego

Radio: 1090-AM, 860-AM (Spanish)s

Today’s matchup

Padres RHP Burch Smith (major league debut)

Smith vs. the Rays: First meeting.

Smith at Tropicana Field: first appearance.

Smith, who turned 23 on April 12, was 1-2 with a 1.15 ERA at Double-A San Antonio. In 31 1/3 innings with the Missions, Smith allowed 17 hits and six walks while striking out 37. That’s better than a 6-to-1 strikeout-to walk ratio. A product of the University of Oklahoma, Smith’s fastball tops out at 98 mph, although he works in the 94-96 range with a 93-mph sinker, a curve and a change. He throws sinker for strikes when behind in count. Smith was 9-6 last season with Single-A Lake Elsinore with a 3.85 ERA in 26 starts. Smith is the first Padre to make his major league debut in an interleague games since Jake Peavy in 2002. He is only the 12th National League pitcher to make his major league debut in an American League ballpark.

Rays vs. Smith

No Tampa Bay player has faced Smith.

Rays RHP Jeremy Hellickson (1-2, 4.79 ERA)

Hellickson vs. the Padres: First meeting.

Hellickson at Tropicana Field: 1-0 this season, 3.38 ERA in three starts.